Protecting the integrity of digital signatures and encrypted communications is an important problem. Many digital signatures and encrypted communications rely on cryptographic keys that are controlled by a signature authority. The signature authority maintains control over the cryptographic keys which are used to generate digital signatures and perform other cryptographic operations. If the signature authority operates as part of a distributed computing environment, cryptographic operations may be performed by a variety of computing entities on behalf of the signature authority. In such situations, the various computing entities acting on behalf of the signature authority may apply digital signatures or establish cryptographically protected communication sessions using a cryptographic key associated with the signature authority. Therefore, controlling the distribution of cryptographic keys from the signature authority to the various computing entities that act on the behalf of the signature authority is an important problem.